Question

我在这段代码中遇到错误;我已将错误消息放在评论中。无法理解。

提前致谢。

#import <Foundation/Foundation.h>

int main (int argc, const char * argv[])
{

    @autoreleasepool {

        NSMutableString *str = [[NSMutableString alloc]init];
        for (int i = 0; i < 10; i++) {
        [str appendString:@"Aaron is cool!\n"];
        }

        // Declare a pointer to an NSError object, but don't instantiate it.
        // The NSError instance will only be created if there is, in fact, an error.
        NSError *error = nil;

        // Pass the error pointer by reference to the NSString method
        BOOL success =[str writeToFile:@"/tmp/cool.txt"; // Expected "]"
          atomically:YES // Bad receiver type 'int'
            encoding:NSUTF8StringEncoding 
               error:&error];

        // Test the returned BOOL, and query the NSError if the write failed
        if (success) {
        NSLog(@"done writing /tmp/cool.txt");
        } else {
        NSLog(@"writing /tmp/cool/txt failed:@", error localizedDescription); //    Expected ')'
        }

    }
    return 0;
}

Answer 1

如果您的代码没有任何拼写错误，那就是问题

// Pass the error pointer by reference to the NSString method
        BOOL success =[str writeToFile:@"/tmp/cool.txt"; // Expected "]"
          atomically:YES // Bad receiver type 'int'
            encoding:NSUTF8StringEncoding 
               error:&error];

删除分号“;”从这里开始。

BOOL success =[str writeToFile:@"/tmp/cool.txt"; // Expected "]"

Answer 2

试试这个：

@autoreleasepool {
    NSMutableString *str = [[[NSMutableString alloc]init] autorelease];
    for (int i = 0; i < 10; i++) {
        [str appendString:@"Aaron is cool!\n"];
    }
    NSError *error = nil;
    BOOL success =[str writeToFile:@"/tmp/cool.txt"
                        atomically:YES
                          encoding:NSUTF8StringEncoding 
                             error:&error];
    if (success) {
        NSLog(@"done writing /tmp/cool.txt");
    } else {
        NSLog(@"writing /tmp/cool/txt failed: %@", [error localizedDescription]); 
    }

}
return 0;

在NSError代码中获取错误

2 个答案: